title: Optimization of arylacetonitrilase production from Alcaligenes sp. MTCC 10675 and its application in mandelic acid synthesis.
abstract: Alcaligenes sp. MTCC 10675 has been isolated from soil sample using enrichment method and has nitrilase catalytic system which is highly specific for the hydrolysis of arylaliphatic nitriles. Optimization of culture conditions using response surface methodology and inducer-mediated approach enhanced arylacetonitrilase production significantly (2.4-fold). Isobutyronitrile acted as an effective inducer for the induction of arylacetonitrilase, and it is highly specific for arylacetonitriles (phenyl acetonitrile and mandelonitrile). Arylacetonitrilase has no effect on its relative velocity (V r) up to 20 mM substrate (mandelonitrile) concentration and at 30 mM mandelonitrile, 23.4 % degree of inhibition (I d) was recorded. Half life of arylacetonitrilase of Alcaligenes sp. MTCC 10675 was 27.5 h at 25 °C. Hg(2+), Ag(+), Pb(3+), and Co(2+) were strong inhibitor of arylacetonitrilase activity which resulted into 100 %, 91 %, 84 %, and 83 % inhibition, respectively. Polar protic solvent (dichloromethane, dimethylsulphooxide, and n-butanol) reduce arylacetonitrilase activity up to 80-94 % at 10 % concentration. Alcaligenes sp. MTCC 10675 has higher biocatalytic activity, i.e., 3.9 gg(-1) dcw, which is highest in comparison to till reported organism. Arylacetonitrilase-mediated hydrolysis of racemic mandelonitrile resulted into R-(-) mandelic acid with 99.0 % enantiomeric excess (e.e.).
authors.affiliation: Department of Biotechnology, Himachal Pradesh University, Summer Hill, Shimla, 171005, India.
authors.forename: S K
authors.initials: SK
authors.lastname: Bhatia
authors.forename: P K
authors.initials: PK
authors.lastname: Mehta
authors.forename: R K
authors.initials: RK
authors.lastname: Bhatia
authors.forename: T C
authors.initials: TC
authors.lastname: Bhalla
mesh_terms: D000097:Acetonitriles / Q000378:metabolism; D000421:Alcaligenes / Q000737:chemistry / Q000201:enzymology* / Q000302:isolation & purification; D000619:Aminohydrolases / Q000737:chemistry / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000378:metabolism; D004795:Enzyme Stability; D015971:Gene Expression Regulation, Enzymologic; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008333:Mandelic Acids / Q000378:metabolism*; D008670:Metals / Q000378:metabolism; D009570:Nitriles / Q000378:metabolism; D012988:Soil Microbiology; D013696:Temperature; D015533:Transcriptional Activation
chemical_list: D000097:Acetonitriles; D004791:Enzyme Inhibitors; D008333:Mandelic Acids; D008670:Metals; D009570:Nitriles; C045516:mandelonitrile; C022246:isobutyronitrile; D000619:Aminohydrolases; C037938:mandelic acid